diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
index 53e388b..586a375 100644
--- a/frc971/control_loops/python/control_loop.py
+++ b/frc971/control_loops/python/control_loop.py
@@ -53,7 +53,7 @@
     return self._namespaces[0]
 
   def _HeaderGuard(self, header_file):
-    return ('_'.join([namespace.upper() for namespace in self._namespaces]) +
+    return ('_'.join([namespace.upper() for namespace in self._namespaces]) + '_' +
             os.path.basename(header_file).upper()
                 .replace('.', '_').replace('/', '_') + '_')